Biomass Combustion with in Situ CO2 Capture with CaO. I. Process Description and Economics

A novel concept is proposed to capture CO2 from biomass, burned in a circulating fluidized bed at a sufficiently low temperature (below 700 degrees C) to allow capture "in situ" by CaO. This step is followed by the calcination of CaCO3 in an interconnected oxy-fuel combustor that delivers a concentrated stream of CO2 suitable for permanent geological storage. A conceptual design and cost estimation exercise is presented and compared with other similar power plant schemes based on biomass and fossil fuels. A sensitivity analysis of the main cost variables reveals that the concept proposed is competitive against other low-carbon systems for lower values of Green Certificates and higher values of a carbon tax. The process could have long-term applications for large-scale biomass-fired systems and medium-term applications in helping large-scale power plants with CO2 capture and storage to meet the target of zero emissions by taking advantage of the negative emissions achieved from CO2 captured from biomass. A second part of this work (see the next article in this issue) demonstrates the concept in a 30 kW circulating fluidized-bed test facility.